ABU DHABI, United Arab Emirates — The nations intervening in Libya pledged as much as $1 billion in support for the opposition there on Thursday as senior officials continued to predict that the collapse of Moammar Gadhafi’s government could be imminent.

As the NATO military alliance intensified attacks in the Libyan capital of Tripoli, including a new round of daytime raids, senior officials meeting here acknowledged reports that Gadhafi’s son, Saif, could be seeking a negotiated exit and said they reflected the government’s isolation and weakness, despite public defiance.

“There have been obviously multiple feelers from the Gadhafi regime to various members of the international community coming every other day,” Australia’s foreign minister, Kevin Rudd, said after a meeting of more than 30 nations and international organizations.

Rudd said the consensus here was that “Gadhafi’s days are well and truly numbered,” giving urgency to the efforts to prepare the opposition for taking power and overseeing a transition. “This is no longer an academic proposition,” he said. “It is a real proposition and one we may be facing sooner than many of you in this room may think.”

Such predictions, echoed again by Secretary of State Hillary Rodham Clinton, have proved premature more than once before since the United States and other NATO nations began a military campaign in March.

In Geneva, a senior Libyan diplomat vehemently denied that Libyan forces had committed atrocities, including a systematic campaign of rapes by soldiers, possibly including the distribution of Viagra, as prosecutors for the International Criminal Court suggested on Wednesday.

Investigations into rape and sexual abuse in war zones are notoriously difficult, and even some human rights groups have cast doubt on the accusations. Amnesty International said in a statement Thursday that the group’s researchers, working in eastern Libya, Misrata and in refugee camps along the Tunisian border, “have not to date turned up significant hard evidence to support this allegation” of systematic rape.

Libyan officials have also steadfastly denied talk of any deal involving Gadhafi’s leaving the country, but even so officials meeting here as part of what is called the “contact group” increasingly took steps to prepare for what Clinton in her remarks called “the inevitable: a post-Gadhafi Libya.”

The officials established a financial mechanism — first agreed on when they met last in Rome a month ago — that would allow direct assistance to the Libyan opposition despite U.N. sanctions that remain in place on the country. That cleared the way for nearly $300 million in assistance already pledged by Kuwait and Qatar, two Arab nations that have strongly supported international action against the Gadhafi government. Italy, France, Turkey, Australia and other countries also pledged additional money on Thursday totaling more than $1 billion, much of it backed by frozen Libyan government assets.